Pump housing construction

ABSTRACT

A pump ( 16 ) has a clamshell housing ( 12, 14 ) with walls ( 34, 36, 46, 50, 52 ) that come together and seal to create chambers ( 22, 24 ) which contain a pressure difference relative to ambient pressure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. application Ser. No. 10/169,566, filed Jul. 2, 2002, issue fee paid, which is based on PCT application PCT/US01/00540, filed on Jan. 8, 2001, which claims benefit to U.S. provisional application Ser. No. 60/175,183, filed Jan. 10, 2000.

STATEMENT OF FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

FIELD OF THE INVENTION

This invention relates to housings or cabinets for pumps such as compressors or vacuum pumps. In particular, this invention concerns such a pump in which clam shell halves of the housing form seals at their abutting edges to define pressure or vacuum chambers or passageways within the housing.

BACKGROUND OF THE INVENTION

In many applications, a compressor or vacuum pump is housed inside a cabinet (a.k.a., housing), which may be molded plastic. In the case of a compressor, the compressor needs intake air, which must be drawn in from outside of the housing and directed to the intake port of the pump, the pump compresses it, and delivers it to a pressurized exhaust port. Typically, tubing is used to direct the output of the exhaust port to a port which is accessible by the user from outside of the housing. The intake air delivered to the pump usually must be filtered, so that only filtered air is delivered to the intake port, and tubing or passageways are required to communicate the filtered air to the intake port.

SUMMARY OF THE INVENTION

The invention provides an improvement to a pump having clam shell housing sections in which each said housing section has one or more walls which seal against one or more walls of the other housing section to define a sealed pressure or vacuum chamber within the walls when the housing sections are brought together. The walls come together to provide a seal all of the way around the chamber, which may be an inlet (or intake) chamber, an outlet (or exhaust) chamber, or a pressurized (including depressurized) passageway, so that a pressure difference can be contained in the chamber, either positive or negative. Thereby, additional tubing or passageways in addition to the housing for routing the intake and outlet of the pump are obviated.

Specifically, the invention provides a pumping unit having a clam shell housing enclosing a motor pump for pumping a working fluid through a flow path in communication with a load outside of the pumping unit. The clam shell housing has first and second sections, each section having inlet walls defining a portion of an intake chamber and outlet walls defining a portion of an exhaust chamber. The inlet walls of the first section seal against the inlet walls of the second section to define a sealed intake chamber in the flow path for passage of the working fluid, and the outlet walls of the first section seal against the outlet walls of the second section to define a sealed exhaust chamber in the flow path for passage of the working fluid.

In a preferred form, the walls are overmolded with an elastomeric sealing material. The walls may seal against one another in end to end contact, or a wall may seal against the side surface of another wall. In the latter case, it is preferred that the sealing edge of the elastomeric sealing material be tapered to make a good seal, and the underlying edge of the wall may also be tapered to help reinforce the sealing material. Edge to side sealing is done with the exposed side of the sealing material facing the high pressure side, so that the pressure helps establish the seal.

At least one of the walls in each housing section may be formed with a half-circular recess in an edge of the wall so that the half circular recesses come together to seal around a circular intake or exhaust port of the motor pump when the housing sections are brought together. One or more holes or tubular ports may also be formed in the walls to create a means for movement of ambient air, such as an inlet or intake port for bring air into the intake chamber and an outlet or exhaust port, to which a tube could be connected, for passing air from the exhaust chamber.

The foregoing and other objects and advantages of the invention will appear in the detailed description which follows. In the description, reference is made to the accompanying drawings which illustrate a preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top perspective view of one clam shell half of a housing containing a compressor;

FIG. 2 is a top plan view of the clam shell half of FIG. 1;

FIG. 3 is a top plan view showing the other clam shell half which mates with the clam shell half shown in FIGS. 1 and 2;

FIG. 4 is a sectional view from the plane of the line 4-4 of FIG. 1, drawn with both clam shell halves assembled together;

FIG. 5 is a cross-sectional view from the plane of the line 5-5 of FIG. 2, drawn with the two clam shell halves assembled together;

FIG. 6 is a cross-sectional view from the plane of the line 6-6 of FIG. 2, drawn with the two clam shell halves assembled together;

FIG. 7 is a cross-sectional view from the plane of the line 7-7 of FIG. 2;

FIG. 8 is a cross-sectional view from the plane of the 8-8 of FIG. 2;

FIG. 9 is a cross-sectional view from the plane of the line 9-9 of FIG. 2; and

FIG. 10 is a top cross-sectional view illustrating the air flow paths through the intake and exhaust chambers defined by the housing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(s)

FIGS. 1 and 2 illustrate one clam shell half 12 of a nebulizer housing and FIG. 3 illustrates the other clam shell half 14. The nebulizer includes a motor pump unit 16 which has an inlet port 18 and an exhaust port 20. The inlet port 18 opens into and draws air from an intake chamber 22 and the exhaust port 20 opens into and expels pressurized air into an exhaust chamber 24. Air is drawn into the intake chamber 22 through a hole 26 in one of the walls of the chamber 22, and a filter (not shown) may be installed in or over the hole 26. Air is exhausted from the exhaust chamber 24 through an outlet port 30 which is formed in one of the walls of the exhaust chamber 24 as shown in FIGS. 9 and 10.

Part of each chamber 22 and 24 is formed by the clam shell half 12 and the other part of each chamber 22 and 24 is formed by the clam shell half 14. Together, walls of the clam shell halves 12 and 14 create the chambers 22 and 24, and the chambers 22 and 24 are sealed against the respective ports 18 and 20 so that the chambers 22 and 24 are sealed except at the respective ports 18, 26, and 20, 30.

The walls of the clam shell halves 12 and 14 which make up the chambers 22, 24 are thin walled molded plastic sections which in each half are integrally molded with the other walls of the half. The clam shell halves 12 and 14 would typically be made of a relatively hard and stiff plastic material such as high impact polystyrene. The walls which make up the chambers 22 and 24 would have a typical thickness of 0.090 inches. The edges of the walls that make up the chambers 22, 24, where they abut all of the way around the respective chamber 22, 24, come together to seal the interiors of the chambers 22, 24 against a pressure difference. However, for the exhaust chamber 24, along wall 34, the edges do not abut, although a wall 36 of the clam shell half 14 abuts the side surface of wall 34.

So that the abutments of the walls of the clam shell half 14 with the walls of the clam shell half 12 may be sufficient so as to create a seal against a pressure difference between the chambers 22 and 24 and atmospheric pressure, at each interface between the walls of the halves 12 and 14, the interfacing surfaces are coated with a relatively soft, e.g. 50 to 60 durometer, thermoplastic elastomer or thermoplastic rubber (TPR) such as Santoprene. This is preferably overmolded onto the edges of the walls that create the seals for the chambers 22, 24. This can be done in a two-shot injection molding process, either in which the harder plastic which makes up the majority of the halves 12 and 14 is first molded in one mold, and then the halves 12 and 14 are put in separate molds to overmold the relatively softer elastomeric material, or in which the harder plastic is molded in one mold in one shot and then cores of the mold are retracted to make room for a shot of the relatively softer material over the edges of the walls that form the chambers 22 and 24.

As shown in FIG. 9, in the case of the seal between the walls 34 and 36, a single TPR gasket 40 is molded onto the edge of the wall 36 and has a tapered configuration so as to generally match the curvature of the surface of the wall 34 and thereby create a seal between the wall 36, to which the gasket 40 is attached, and the wall 34 which abuts the gasket 40. On the other side of the chamber 24, a gasket 44 is overmolded onto the edge of wall 46 and a gasket 48 is overmolded onto the edge of wall 50. The gaskets 44 and 48 abut each other to create a seal between them, and thereby create a seal between the walls 46 and 50. A gasketed interface is provided all of the way around each chamber 22 and 24. Thereby, the only inlet to chamber 22 is hole 26 and the only outlet is port 18, and the only inlet to chamber 24 is port 20 and the only outlet is port 30. In normal operation, chamber 22 is subjected to quite low pressure differences, being an intake chamber, with the only pressure difference being created by a filter which may be installed in hole 26, but chamber 24 may be subjected to pressures on the order of about 15 psi.

FIGS. 5 and 6 illustrate how seals are created around the ports 18 and 20 of the motor pump unit 16. Semi-circles are formed in the walls of the two halves 12 and 14 which, when the edges of the semi-circular openings are overmolded with the relatively soft gasket material, closely mate with the outside diameters of the ports 18 and 20 so as to cradle the ports. As an enhancement to the invention, rather than gaskets such as the gasket 44 and 48 meeting along a flat surface, one of the gaskets 44, 48 may be formed with a pointed edge and the other gasket 44, 48 may be formed flat, or with a V-shaped groove to receive the pointed edge to create a form fit, to thereby create a more reliable seal.

FIGS. 7 and 8 illustrate seals that are created for the intake chamber 22. The above description for the seals of the exhaust chamber 24 applies to the exhaust chamber 22 as well, although with different walls and gasket edges meeting. In FIG. 7, mating overmolded gaskets are identified by reference numbers 60; 62 and 64; 66. In FIG. 8, mating overmolded gaskets are identified by reference numbers 68, 70. In FIG. 8, a relatively tall wall 52 has gasket material 56 at its end, which is tapered, and the gasket material 56 is also tapered to press up against the side of wall 34 of the half 12. The tapering of the end of the wall 52 helps stiffen the gasket 56 against bending to improve the seal against the curved surface of the wall 34 which is created by pressing the gasket 56 against it.

The two cabinet halves 12, 14 are held together by any suitable means, such as snap fits, fasteners through holes 80, a combination of snap fits and fasteners, or any other suitable means.

Many modifications and variations to the preferred embodiment described will be apparent to those skilled in the art which will still embody the invention. For example, a sealed passageway incorporating the invention could be made in any shape. Therefore the invention should not be limited to the preferred embodiment described. 

1. A pumping unit comprising: a motor pump for pumping a working fluid through a flow path in communication with a load outside of the pumping unit; and a clam shell housing having first and second sections enclosing the motor pump, each section having inlet walls defining a portion of an intake chamber and outlet walls defining a portion of an exhaust chamber, wherein the inlet walls of the first section seal against the inlet walls of the second section to define a sealed intake chamber in the flow path for passage of the working fluid and wherein the outlet walls of the first section seal against the outlet walls of the second section to define a sealed exhaust chamber in the flow path for passage of the working fluid.
 2. The pumping unit of claim 1, wherein at least one of the inlet and outlet walls has an edge which is overmolded with an elastomeric seal material.
 3. The pumping unit of claim 1, wherein the intake and exhaust chambers are in communication with associated inlet and outlet ports of the pumping unit.
 4. The pumping unit of claim 1, wherein an edge of at least one of the inlet and outlet walls in each of the first and second sections contains a half-circular recess, and wherein the half circular recesses come together to seal around a circular port of the pumping unit when the first and second sections are brought together.
 6. The pumping unit of claim 1, wherein the inlet walls of first and second sections mate in end to end contact to define at least part of the intake chamber and the outlet walls of the first and second sections mate in end to end contact to define at least part of the exhaust chamber.
 7. The pumping unit of claim 1, wherein an end of at least one of the inlet and outlet walls of at least one of the first and second sections seals against a side surface of at least one of the inlet and outlet walls of the other of the first and second sections to define at least part of at least one of the intake and exhaust chambers.
 8. The pumping unit of claim 7, wherein the end is tapered.
 9. The pumping unit of claim 8, wherein the end is overmolded with an elastomeric sealing material.
 10. The pumping unit of claim 9, wherein the elastomeric sealing material is tapered.
 11. The pumping unit of claim 1, wherein at least one of the inlet and outlet walls includes at least a portion of an intake port formed therein.
 12. The pumping unit of claim 1, wherein at least one of the inlet and outlet walls includes at least a portion of an exhaust port formed therein.
 13. The pumping unit of claim 1, wherein the inlet walls of the first and second sections seal against an intake port of the motor pump and the outlet walls of the first and second sections seal against an exhaust port of the motor pump.
 14. The pumping unit of claim 1, wherein inlet walls of the first and second sections seal against one another in end to end contact.
 15. The pumping unit of claim 1, wherein outlet walls of the first and second sections seal against one another in end to end contact.
 16. The pumping unit of claim 1, wherein end edges of the inlet and outlet walls of the first and second sections are overmolded with an elastomeric sealing material.
 17. The pumping unit of claim 16, wherein the end edges are tapered.
 18. A pumping unit comprising: a motor pump for pumping a working fluid through a flow path in communication with a load outside of the pumping unit; and a clam shell housing having first and second sections enclosing the motor pump, each of the first and second sections has one or more walls that seal against one or more walls of the other section to define a sealed pressure or vacuum chamber of the working fluid within the walls when the first and second sections are brought together to enclose the motor pump. 